Conventionally, an automatic analyzer is used that automatically measures the amount of a predetermined component in a sample by detecting the reaction between the sample and a reagent in, for example, biochemical tests or laboratory tests. In this measurement with the automatic analyzer, cartridges are used that have reagent tanks filled with reagents as well as reaction tanks in which a sample and a reagent are reacted with each other (see, for instance, Patent Documents 1 to 3).
FIG. 8 shows an example of a conventional cartridge. As shown in FIG. 8, the cartridge 800 includes a plurality of (10 in this example) tanks 810 to 819 that are disposed in parallel with each other in the longitudinal direction and are unified with a plate member. The upper parts of the plurality of tanks 810 to 819 are open. Once this cartridge 800 is set on an automatic analyzer, a sample or a reagent that has been stored in each of the plurality of tanks 810 to 819 is introduced or led out with a vertically and horizontally movable pipette provided for the automatic analyzer.
In the measurement that is carried out using such a cartridge, when, for example, a sample or a reagent remains at the leading end of the pipette, the measurement reliability is deteriorated. In the case where the residual liquid present in/on the pipette is not removed, it is necessary to replace the chip mounted on the leading end of the pipette every time a liquid is drawn therein or discharged therefrom. Accordingly, it is necessary to remove the residual liquid present at the leading end of the pipette. The method of removing the residual liquid is, for example, a method that includes providing a waste liquid tank for the cartridge and bringing a side face of the pipette into contact with a side wall of the waste liquid tank. In this method, however, it is difficult to remove the liquid that has adhered to the opposite side face of the pipette to the side that is brought into contact with a side wall of the waste liquid tank.
Furthermore, there are methods for removing the residual liquid by completely discharging the air in the pipette or by blowing air onto the leading end of the pipette. In these methods, however, an air feeder must be provided and any highly viscous liquid tends to remain in the pipette.
Furthermore, various methods have been proposed in which the leading end of the pipette is brought into contact with filter paper and thereby the residual liquid is absorbed thereby (see, for example, Patent Documents 4 to 10). However, this method requires equipment for recovering the used filter paper (after absorption) and providing a new filter paper.    [Patent Document 1] JP 58-36359 U    [Patent Document 2] JP 8-122336 A    [Patent Document 3] JP 11-316226 A    [Patent Document 4] JP 51-35393 A    [Patent Document 5] JP 51-37691 A    [Patent Document 6] JP 58-48647 U    [Patent Document 7] JP 58-193255 U    [Patent Document 8] JP 60-243566 A    [Patent Document 9] JP 7-3329 U    [Patent Document 10] JP 2669821 B